I have a Wellcraft Portofino that I have owned for several years.
When I bought the boat it had an AM/FM CD player in the cockpit that worked fine. I added a car style radio to the salon about three years ago. I wired the unit properly and attached the “memory” lead to an empty, fused position on the same 12 volt bus as the cockpit radio.
From day one the salon radio would lose it’s memory on engine start while the cockpit radio did not. In between engines starts is not a problem. I double checked my wiring, which seemed good and wrote the problem up to buying a cheap radio on sale.
Midway through last season I replaced the cockpit AM/FM radio with a new Sony Marine unit. I now have the same problem with this radio! The tuner memory holds until I start engines. I just don’t get it!
The marine electrical is set up with two battery banks. The starboard bank is a 4-D and starts that engine and navigation equipment including the cockpit Sony radio. The port bank is a bank of four 6 volt deep cycle batteries wired series/parallel for 12 volts that start the port engine and also supplies the house.
I have checked all of the radio connections. I have switched the memory lead from the original fuse panel to different bus bars. Nothing has helped, as soon as I start an engine with the same battery bank the the AM/FM radio memory leads are attached to, the memories go blank.
I am starting to think that this is a surge problem. I believe I have confirmed this by using my master boat battery switches to start engines on the battery bank that does not have the radio memory. If I do that there is no memory loss. Starting and running my boat in this manner is not practical for me and leaves open the possibility of draining the wrong battery bank.
This situation is really starting to drive me nuts, I’d greatly appreciate any recommendations you may have.
Stereo memory circuits are sensitive to low voltage and you are suffering for a voltage drop “stack up” and will reset after only a few milliseconds of low voltage. This is very common with newer, higher draw, higher tech stereos.
The power feed to your helm has a drop. The more current that you draw through it, the more the voltage drop in the circuit. When higher draw devices such as bilge blowers, cockpit lights, stereos, the voltage drop is even higher. Slightly corroded connections induce voltage drops. When you start the engine, the source voltage (the battery) drops lower which makes the stereo input voltage that much lower.
- Increase the size of the power feed wiring and ground to your helm panel.
- Run a dedicated power and ground lead from the battery to the stereo.
- Make sure you use circuit protection at the source of power. An increase of 0.1 volts will mean the difference between the stereo memory resetting and remaining.
Hope this helps,